Integrated hydrocracking and fluidized catalytic cracking system and process

ABSTRACT

A system and method of cracking hydrocarbon feedstocks is provided that allows for significant flexibility in terms of the desired product yield. An integrated process includes introducing the feedstock and hydrogen into a first hydrocracking reaction zone containing a first hydrocracking catalyst to produce a first zone effluent. The first zone effluent is passed to a fractionating zone to produce at least a low boiling fraction and a high boiling fraction, and optionally one or more intermediate fractions. The bottoms fraction is conveyed to a fluidized catalytic cracking reaction and separation zone, from which olefins and gasoline are recovered. At least a portion of remaining cycle oil is passed from the fluidized catalytic cracking reaction and separation zone to a second hydrocracking reaction zone containing a second hydrocracking catalyst to produce a second stage effluent. At least a portion of the second stage effluent is recycled to the fractionating zone and/or the first hydrocracking reaction zone.

RELATED APPLICATIONS

Not applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to integrated cracking systems andprocesses that combine hydrocracking and fluidized catalytic crackingoperations, in particular for enhanced flexibility in the production oflight olefinic and middle distillate products.

2. Description of Related Art

Hydrocracking processes are used commercially in a large number ofpetroleum refineries. They are used to process a variety of feedsboiling in the range of 370° C. to 520° C. in conventional hydrocrackingunits and boiling at 520° C. and above in the residue hydrocrackingunits. In general, hydrocracking processes split the molecules of thefeed into smaller, i.e., lighter, molecules having higher averagevolatility and economic value. Additionally, hydrocracking processestypically improve the quality of the hydrocarbon feedstock by increasingthe hydrogen to carbon ratio and by removing organosulfur andorganonitrogen compounds. The significant economic benefit derived fromhydrocracking operations has resulted in substantial development ofprocess improvements and more active catalysts.

Mild hydrocracking or single stage once-through hydrocracking occurs atoperating conditions that are more severe than hydrotreating processes,and less severe than conventional full pressure hydrocracking processes.This hydrocracking process is more cost effective, but typically resultsin lower product yields and quality. The mild hydrocracking processproduces less mid-distillate products of a relatively lower quality ascompared to conventional hydrocracking. Single or multiple catalystssystems can be used depending upon the feedstock processed and productspecifications. Single stage hydrocracking is the simplest of thevarious configurations, and is typically designed to maximizemid-distillate yield over a single or dual catalyst systems. Dualcatalyst systems can be deployed as a stacked-bed configuration or inmultiple reactors.

In a series-flow configuration the entire hydrotreated/hydrocrackedproduct stream from the first reactor, including light gases (e.g.,C₁-C₄, H₂S, NH₃) and all remaining hydrocarbons, are sent to the secondreactor. In two-stage configurations the feedstock is refined by passingit over a hydrotreating catalyst bed in the first reactor. The effluentsare passed to a fractionator column to separate the light gases, naphthaand diesel products boiling in the temperature range of 36° C. to 370°C. The hydrocarbons boiling above 370° C. are then passed to the secondreactor for additional cracking.

In fluidized catalytic cracking (FCC) processes, petroleum derivedhydrocarbons are catalytically cracked with an acidic catalystmaintained in a fluidized state, which is regenerated on a continuousbasis. The main product from such processes has generally been gasoline.Other products are also produced in smaller quantities via FCC processessuch as liquid petroleum gas and cracked gas oil. Coke deposited on thecatalyst is burned off at high temperatures and in the presence of airprior to recycling regenerated catalyst back to the reaction zone.

In recent years there has been a tendency to produce, in addition togasoline, light olefins by FCC operations, which are valuable rawmaterials for various chemical processes. These operations havesignificant economic advantages, particularly with respect to oilrefineries that are highly integrated with petrochemical productionfacilities.

There are different methods to produce light olefins by FCC operations.Certain FCC operations are based on a short contact time of thefeedstock with the catalyst, e.g., as disclosed in U.S. Pat. Nos.4,419,221, 3,074,878, and 5,462,652, which are incorporated by referenceherein. However, the short contact time between feedstock and catalysttypically results in relatively low feed conversion.

Other FCC operations are based on using pentasil-type zeolite, forinstance, as disclosed in U.S. Pat. No. 5,326,465, which is incorporatedby reference herein. However, the use of a pentasil-type zeolitecatalyst will only enhance the yield of light fraction hydrocarbons byexcessive cracking of the gasoline fraction, which is also a high valueproduct.

Additional FCC operations are based on carrying out the crackingreactions at high temperature, such as that disclosed in U.S. Pat. No.4,980,053, which is incorporated by reference herein. However, thismethod can result in relatively high levels of dry gases production.

Further FCC operations are based on cracking the feed oil at hightemperature and short contact time and using a catalyst mixture ofspecific base cracking catalyst and an additive containing ashape-selective zeolite, as disclosed in U.S. Pat. No. 6,656,346, whichis incorporated by reference herein. Processes based on this method arealso known as High Severity Fluidized Catalytic Cracking (HS-FCC).Features of this process include a downflow reactor, high reactiontemperature, short contact time, and high catalyst to oil ratio.

Downflow reactors permits higher catalyst to oil ratio, since lifting ofsolid catalyst particles by vaporized feed is not required, and this isparticularly suitable for HS-FCC. In addition, HS-FCC processes areoperated under considerably higher reaction temperatures (550° C. to650° C.) as compared to conventional FCC processes. Under these reactiontemperatures, two competing cracking reactions occur, thermal crackingand catalytic cracking. Thermal cracking contributes to the formation oflighter products, such as dry gas and coke, whereas catalytic crackingincreases propylene and butylene yield. The short residence time in thedownflow reactor is also favorable to minimize thermal cracking.Undesirable secondary reactions such as hydrogen-transfer reactions,which consume olefins, are suppressed. The desired short residence timeis attained by mixing and dispersing catalyst particles and feed at thereactor inlet followed by immediate separation at the reactor outlet. Inorder to compensate for the decrease in conversion due to the shortcontact time, the HS-FCC process is operated at relatively highcatalysts to oil ratios.

While individual and discrete hydrocracking and FCC processes arewell-developed and suitable for their intended purposes, therenonetheless remains a need for increased flexibility, efficiency andhigh-value product yield in refinery operations.

SUMMARY OF THE INVENTION

In accordance with one or more embodiments, the invention relates to asystem and method of cracking hydrocarbon feedstocks in a manner thatallows for significant flexibility in terms of the desired productyield.

In accordance with one or more embodiments, an integrated process forconversion of a feedstock is provided, in particular for feedstockscontaining hydrocarbons having a boiling point greater than 300° C. Theintegrated process, including hydrocracking and fluidized catalyticcracking, includes the steps of:

a. introducing the feedstock and hydrogen into a first hydrocrackingreaction zone containing a first hydrocracking catalyst to produce afirst zone effluent;

b. passing the first zone effluent to a fractionating zone to produce atleast a low boiling fraction and a high boiling fraction, and optionallyone or more intermediate fractions;

c. passing the bottoms fraction to a fluidized catalytic crackingreaction and separation zone operating under conditions that promoteformation of olefins and gasoline and that minimize olefin-consumingreactions;

d. recovering olefins from the fluidized catalytic cracking reaction andseparation zone;

e. recovering gasoline from the fluidized catalytic cracking reactionand separation zone;

f. conveying at least a portion of remaining cycle oil from thefluidized catalytic cracking reaction and separation zone, and hydrogen,to a second hydrocracking reaction zone containing a secondhydrocracking catalyst to produce a second stage effluent; and

g. recycling at least a portion of the second stage effluent to thefractionating zone and/or the first hydrocracking reaction zone.

Still other aspects, embodiments, and advantages of these exemplaryaspects and embodiments, are discussed in detail below. Moreover, it isto be understood that both the foregoing information and the followingdetailed description are merely illustrative examples of various aspectsand embodiments, and are intended to provide an overview or frameworkfor understanding the nature and character of the claimed aspects andembodiments. The accompanying drawings are included to provideillustration and a further understanding of the various aspects andembodiments, and are incorporated in and constitute a part of thisspecification. The drawings, together with the remainder of thespecification, serve to explain principles and operations of thedescribed and claimed aspects and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in further detail below and withreference to the attached drawings all of which describe or relate toapparatus, systems and methods of the present invention. For the purposeof illustrating the invention, there are shown in the drawingsembodiments which are presently preferred, with optional unitoperations, inlets, outlets and/or streams shown in dashed lines. In thefigures, which are not intended to be drawn to scale, each similarcomponent that is illustrated in various figures is represented by alike numeral. In the figures:

FIG. 1 is a process flow diagram of an integrated hydrocracking andfluidized catalytic cracking system described herein;

FIG. 2 is a generalized diagram of a downflow fluidized catalyticcracking reactor system; and

FIG. 3 is a generalized diagram of a riser fluidized catalytic crackingreactor system.

DETAILED DESCRIPTION OF THE INVENTION

Integrated processes and apparatus are provided for the refining andhydrocracking hydrocarbon feeds, such as vacuum gas oil, to obtainimproved yields and higher quality products, including light olefinspropylene and butylenes, and middle distillate products. Typically, ahydrocracking unit does not produce light olefins, and conventional orhigh severity FCC processes do not produce mid distillates suitable foruse as transportation fuel. However, the integrated processes andapparatus provided herein produces both light olefins and middledistillate products while minimizing production of side products, as allor most unconverted bottoms are processed within the battery limits ofthe integrated unit. According to the present processes and apparatus,the overall middle distillate yield is improved as the first stagehydrocracking effluents are topped in a fractionator, and only bottoms(e.g., boiling at 370° C. and above) are passed to the FCC reaction andseparation zone for cracking, thus further cracking heavy fractions intomiddle distillates (e.g., boiling in the range of 180° C. to 370° C.).

Importantly, by integrating hydrocracking and FCC operations, a level offlexibility is attained that is not possible by the individual,non-integrated processes. For instance, in operations in which thehydrocracking unit conversion is relatively high, e.g., 80 V %, due tofactors including but not limited to reactor selection, catalyst type,extent of catalytic activity reduction, operating conditions and theparticular characteristics of the feedstock, there will be lessfeedstock to the FCC unit and as a result the integrated unit willproduce more naphtha and diesel product and less light olefins such aspropylene. On the other hand, in operations in which the hydrocrackingunit conversion is relatively low level, e.g., 60 V %, there will be arelative increase in feedstock to the FCC unit thereby resulting in arelatively higher level of olefinic product. Table 1 shows exemplaryvolume percentage yields for olefin, naphtha and middle distillateproducts relative to the conversion level in the hydrocracking unit.Notably, the olefin yield can range from as high as about 19 V % whenthe hydrocracker conversion is only 20 V % to 0 V % when thehydrocracker conversion is 100 V %, wherein the volume percentages arebased on the volume of initial feed.

TABLE 1 Hydrocracker Olefin Naphtha Middle Distillate Conversion FCCFeed* Yield Yield Yield 20 80 19.2 7.17 12.06 30 70 16.8 10.76 18.09 4060 14.4 14.34 24.11 50 50 12 17.93 30.14 60 40 9.6 21.51 36.17 70 30 7.225.10 42.20 80 20 4.8 28.69 48.23 90 10 2.4 32.27 54.26 100 0 0 35.8660.29 *The FCC feed values are approximate and based on thehydrocracking conversion level. The values may be slightly higher orlower due to the composition of gas feed and quantities of hydrogenincorporated in the hydrocracker.

In general, the process and apparatus for improved cracking include afirst hydrocracking reaction zone in which the feedstock is hydrotreated(i.e., hydrodesulfurized, hydrodenitrognized, hydrogenated) and crackedin the presence of hydrogen. Effluents from the first hydrocrackingreaction zone, containing cracked hydrocarbons yielded from the firsthydrocracking reaction zone, partially cracked hydrocarbons andunconverted hydrocarbons, are fractionated. Fractionator bottomsincluding unconverted hydrocarbons and any cracked hydrocarbons and/orpartially cracked hydrocarbons boiling above a predetermined fluidizedcatalytic cracking feed cut point are passed to a fluidized catalyticcracking (FCC) reaction and separation zone. The FCC charge is cracked,and the FCC effluent is separated in into light olefins and gasolinethat result from the cracking reactions, and heavier componentsincluding unconverted hydrocarbons and partially cracked hydrocarbons,e.g., cycle oils. The heavier components are further hydrogenated andcracked in a second hydrocracking reaction zone, with effluents returnedto the fractionator upstream from the FCC reaction and separation zone.

In particular, and referring to FIG. 1, a flow diagram of integratedhydrocracking and fluidized catalytic cracking apparatus 6 is provided.Apparatus 6 includes a first hydrocracking reaction zone 12 containing afirst hydrocracking catalyst, a fractionating zone 16, an FCC reactionand separation zone 32 and a second hydrocracking reaction zone 46containing a second hydrocracking catalyst.

First hydrocracking reaction zone 12 includes a feed inlet 11 forreceiving feedstock and hydrogen gas. Inlet 11 is in fluid communicationwith a source of feedstock via a conduit 8 and a source of hydrogen viaa conduit 10. In additional embodiments a first hydrocracking reactionzone can include a separate feedstock inlet and one or more separatehydrogen inlets.

In first hydrocracking reaction zone 12, an intermediate product isproduced including gases, naphtha, middle distillates and higher boilinghydrocarbons, including partially cracked hydrocarbons and unconvertedhydrocarbons. The intermediate product is discharged via a firsthydrocracking reaction zone outlet 14 and is conveyed to thefractionating zone 16.

Fractionating zone 16 includes an inlet 15 in fluid communication withthe first hydrocracking reaction zone outlet 14. In addition, asdescribed below, inlet 15 is also in fluid communication with a secondhydrocracking reaction zone outlet 47, so that the combined charge isfractioned in zone 16.

In one embodiment, the combined charge is fractioned into overhead gas,e.g., containing molecules having a boiling point below about 36° C.,that is discharged via an outlet 18; optionally one or more intermediatefractions including a naphtha fraction having a boiling point in therange of about 36° C. to about 180° C. that is discharged via outlet 20and a middle distillate fraction having a boiling point in the range ofabout 180° C. to about 370° C. that is discharged via outlet 22; and abottoms fraction, e.g., having an initial boiling point of about 370°C., that is discharged via outlet 24. A portion 18 a of the overheadgases, after separation and cleaning, can be recycled to firsthydrocracking reaction zone 12 and/or second hydrocracking reaction zone46.

In another embodiment, the combined charge is fractioned into a lowboiling fraction that is discharged via outlet 18, an intermediateboiling fraction that is discharged via an outlet (which can be one ofeither outlet 20 or outlet 22, whereby the other outlet is not required)and a high boiling fraction that is discharged via outlet 24. Theintermediate boiling fraction can be passed to downstream unitoperations (not shown) for further separation or processing, e.g., intoa naphtha fraction and a middle distillate fraction.

In an additional embodiment, naphtha and/or middle distillates from thefractionating zone 16 can be passed to the FCC reaction and separationzone 32 (not shown in FIG. 1), for instance, for conversion into lightolefins and/or gasoline. The naphtha and/or middle distillates can beconveyed along with the high boiling fraction. Alternatively, naphthaand/or middle distillates can be conveyed separately from the highboiling fraction to different risers or downers in the FCC unit, or toseparate FCC units.

In a further embodiment, the combined charge is fractioned into a lowboiling fraction that is discharged via outlet 18 and a high boilingfraction that is discharged via outlet 24 (whereby outlets 20 and 22 arenot required). The cut point for the fractionator in this embodiment canbe, for instance, 370° C., in which a naphtha fraction boiling in therange of about 36° C. to about 180° C. and a middle distillate fractionboiling in the range of about 180° C. to about 370° C. are dischargedalong with overhead gases, and passed to downstream unit operations (notshown) for further separation or processing, including collection ofnaphtha and middle distillate. A portion 18 a of the overhead gases,including hydrogen and light hydrocarbons such as C₁ to C₄, can berecycled to first hydrocracking reaction zone 12 and/or secondhydrocracking reaction zone 46 after separation and cleaning.

In certain embodiments, an optional bleed outlet 49 is provided in fluidcommunication with the discharge stream from outlet 24 to remove heavypoly nuclear aromatic compounds, which could causes equipment fouling.The portion of the bottoms or high boiling fraction that is bled can beabout 0 V % to about 10 V %, in certain embodiments about 1 V % to about5 V % and in further embodiments about 1 V % to about 3 V %.

The bottoms fraction or high boiling fraction that is discharged viaoutlet 24 is conveyed to FCC reaction and separation zone 32 thatoperates under conditions that promote formation of olefins whileminimizing olefin-consuming reactions, such as hydrogen-transferreactions. FCC reaction and separation zone 32 generally includes one ormore reaction sections in which the charge and an effective quantity offluidized cracking catalyst are introduced. In addition, FCC reactionand separation zone 32 includes a regeneration section in which crackingcatalysts that have become coked, and hence access to the activecatalytic sites becomes limited or nonexistent, are subjected to hightemperatures and a source of oxygen to combust the accumulated coke andsteam to strip heavy oil adsorbed on the spent catalyst. In addition,FCC reaction and separation zone 32 includes a separation apparatus,such as a fractionating tower, to partition the FCC reaction productsinto olefins, gasoline and heavy products. While arrangements of certainFCC units are described herein with respect to FIGS. 2 and 3, one ofordinary skill in the art will appreciate that other well-known FCCunits can be employed.

In general, FCC reaction and separation zone 32 includes a feed inlet 28in fluid communication with the high boiling or bottoms outlet 24 of thefractionating zone 16. In additional embodiments, a source of feedstockthat is separate from the feedstock introduced to first hydrocrackingreaction zone 12 is optionally conveyed into FCC reaction and separationzone 32, e.g., via a conduit 26. This feedstock can be the same ordifferent in its characteristics than the feedstock to introduced tofirst hydrocracking reaction zone 12. In certain embodiments, thefeedstock introduced via conduit 26 is treated vacuum gas oil having lowsulfur and nitrogen content. In addition, steam can be integrated withthe feed 28 to atomize or disperse the feed into the FCC unit.

FCC reaction and separation zone 32 includes plural outlets fordischarging products, partially cracked hydrocarbons, unreactedhydrocarbons and by-products. In general, effluent from the fluidizedcatalytic cracking reactor is fractioned and discharged via a water andgas outlet 34, an olefin outlet 36, a gasoline outlet 38, a light cycleoil outlet 40 and a heavy cycle oil outlet 41. In certain embodiments,both light and heavy cycle oil can be discharged via a single outlet.Olefins and gasoline are recovered and collected as final orintermediate products, i.e., that can be subjected to further downstreamseparation and/or processing.

Cycle oil, including light cycle oil from FCC reaction and separationzone outlet 40 and heavy cycle oil from FCC reaction and separation zoneoutlet 41, are combined and passed, e.g., via a conduit 43, to secondhydrocracking reaction zone 46. A bleed stream 42, which is a slurry oilstream that is heavier than the heavy cycle oil stream and typicallycontains catalyst particles, can also be discharged from the FCCreaction and separation zone 32. Second hydrocracking reaction zone 46includes an inlet 45 for receiving cycle oil and hydrogen, which is influid communication with conduit 43 and a source of hydrogen via aconduit 44. In additional embodiments a second hydrocracking reactionzone can include a separate cycle oil inlet and one or more separatehydrogen inlets. Note that the source of hydrogen can be the same sourceas that feeds first hydrocracking reaction zone 12, or a separatesource. For instance, in certain systems, it can be desirable to providehydrogen of different purity levels and/or hydrogen partial pressure tofirst hydrocracking reaction zone 12 and second hydrocracking reactionzone 46.

In second hydrocracking reaction zone 46, an intermediate product isproduced including gases, naphtha, middle distillates and higher boilinghydrocarbons, including partially cracked and unconverted hydrocarbons.An intermediate product stream is discharged via a second zone outlet 47that is passed via a conduit 48 to fractionating zone 16 along with theintermediate product stream from the first hydrocracking reaction zone12.

In certain optional embodiments, at least a portion of the secondhydrocracking reaction zone intermediate product can be recycled, e.g.,via a conduit 50, to inlet 11 of first hydrocracking reaction zone 12.

Advantageously, in the process of the present invention, middledistillate production can be about 10 V % to about 60 V %, in certainembodiments about 20 V % to about 50 V %, and in further embodimentsabout 20 V % to about 40 V %, based on the initial feed via inlets 8 and26. In addition, light olefin production can be about 3 V % to about 20V %, in certain embodiments about 5 V % to about 20 V %, and in furtherembodiments about 10 V % to about 20 V %, based on the initial feed viainlets 8 and 26. As set forth in Table 1 above, light olefin productionand middle distillate production are approximately inverselyproportional, i.e., as middle distillate production decreases bylowering the level of hydrocracker conversion, more feed is passed tothe FCC operation thereby increasing production of light olefins.

The initial feedstock for use in above-described apparatus and process(i.e., introduced via conduit 8 and optionally via conduit 26) can be apartially refined oil product obtained from various sources. In general,the feedstock contains hydrocarbons having boiling point greater thanabout 300° C., and in certain embodiments in vacuum gas oil range ofabout 370° C. to about 600° C. The source of the partially refined oilfeedstock can be crude oil, synthetic crude oil, bitumen, oil sand,shell oil, coal liquids, or a combination including one of the foregoingsources. For example, the partially refined oil feedstock can be vacuumgas oil, deasphalted oil and/or demetallized oil obtained from a solventdeasphalting process, light coker or heavy coker gas oil obtained from acoker process, cycle oil obtained from an FCC process separate from theintegrated FCC process described herein, gas oil obtained from avisbreaking process, or any combination of the foregoing partiallyrefined oil products. In certain embodiments, vacuum gas oil is asuitable initial feedstock for the integrated cracking process.

The first hydrocracking reaction zone and the second hydrocrackingreaction zone can include the same type of reactor or different types ofreactors. Suitable reaction apparatus include fixed bed reactors movingbed reactor, ebullated bed reactors, baffle-equipped slurry bathreactors, stirring bath reactors, rotary tube reactors, slurry bedreactors, or other suitable reaction apparatus as will be appreciated byone of ordinary skill in the art. In certain embodiments, and inparticular for vacuum gas oil and similar feedstocks, fixed bed reactorsare utilized for both the first and second hydrocracking reaction zones.In additional embodiments, and in particular for heavier feedstocks andother difficult to crack feedstocks, ebullated bed reactors are utilizedfor both the first and second hydrocracking reaction zones.

In general, the operating conditions for the reactor in a hydrocrackingreaction zone include:

reaction temperature of about 300° C. to about 500° C., in certainembodiments about 330° C. to about 475° C., and in further embodimentsabout 330° C. to about 450° C.;

hydrogen partial pressure of about 60 Kg/cm² to about 300 Kg/cm², incertain embodiments about 100 Kg/cm² to about 200 Kg/cm², and in furtherembodiments about 130 Kg/cm² to about 180 Kg/cm²;

-   -   liquid hourly space velocity (LHSV) of about 0.1 h⁻¹ to about 10        h⁻¹, in certain embodiments about 0.25 h⁻¹ to about 5 h⁻¹, and        in further embodiments of 0.5 h⁻¹ to 2 h⁻¹; and    -   hydrogen/oil ratio of about 500 normalized m³ per m³ (Nm³/m³) to        about 2500 Nm³/m³, in certain embodiments about 800 Nm³/m³ to        about 2000 Nm³/m³, and in further embodiments about 1000 Nm³/m³        to about 1500 Nm³/m³.

A catalyst that is suitable for the particular charge and the desiredproduct is maintained in the hydrocracking reactors within the zones. Asis known to those having ordinary skill in the art, the catalyst can bedifferent in the first and second zones.

In certain embodiments, the first zone hydrocracking catalyst includesany one of or combination including amorphous alumina catalysts,amorphous silica alumina catalysts, zeolite based catalyst. The firstzone hydrocracking catalyst can possess an active phase materialincluding, in certain embodiments, any one of or combination includingNi, W, Mo, or Co.

In certain embodiments in which an objective in the first hydrocrackingreaction zone is hydrodenitrogenation, acidic alumina or silica aluminabased catalysts loaded with Ni—Mo or Ni—W active metals, or combinationsthereof, are used. Hydrodenitrogenation reactions are commonly targetedin the first hydrocracking reaction zone as second hydrocrackingreaction zone catalysts can be provided that commonly not tolerant tothe presence of nitrogen. Hydrodesulfurization reactions also occur atthe process pressures and temperatures using these hydrodenitrogenationcatalysts. A substantial amount of sulfur compounds are converted at thehydrodenitrogenation conditions. In embodiments in which the objectiveis to remove all nitrogen and to increase the conversion ofhydrocarbons, silica alumina, zeolite or combination thereof are used ascatalysts, with active metals including Ni—Mo, Ni—W or combinationsthereof

In certain embodiments, the second zone hydrocracking catalyst includesany one of or combination including zeolite based catalysts, amorphousalumina catalysts, amorphous silica alumina catalysts. In order toeffectively convert refined and partially cracked feedstocks intolighter fractions, suitable catalysts include acidic catalysts such assilica alumina, zeolite or combinations thereof, with active metalsincluding Ni—Mo, Ni—W or combinations thereof

Catalytic cracking reactions occur in FCC reaction and separation zone32 under conditions that promote formation of olefins and that minimizeolefin-consuming reactions, such as hydrogen-transfer reactions. Theseconditions generally depend on the type and configuration of the FCCunit.

Various types of fluidized catalytic cracking reactors operate underconditions that promote formation of olefins and gasoline are known,including the High-Severity FCC process developed by Nippon OilCorporation of Japan, Deep Catalytic Cracking (DCC-I and DCC-II) andCatalytic Pyrolysis Process developed by SINOPEC Research Institute ofPetroleum Processing of Beijing, China, the Indmax process developed byIndian Oil Corporation of India, MAXOFIN™ developed by ExxonMobil ofIrving, Tex., USA and KBR, Inc. of Houston, Tex., USA, NExCC™ developedby Fortum Corporation of Fortum, Finland, PetroFCC developed by UOP LLCof Des Plaines, Ill., USA, Selective Component Cracking developed by ABBLummus Global, Inc. of Bloomfield, N.J., USA, High-Olefins FCC developedby Petrobras of Brazil, and Ultra Selective Cracking developed by Stone& Webster, Incorporated of Stoughton, Mass., USA.

In certain embodiments, a suitable high severity fluidized catalyticcracking unit operation includes a downflow reactor and is characterizedby high reaction temperature, short contact time and high catalyst tooil ratio. A downflow reactor permits higher catalyst to oil ratiobecause the requirement to lift the catalyst by vaporized feed is notrequired. Reaction temperatures are in the range of about 550° C. toabout 650° C., which is higher than conventional fluidized catalyticcracking reaction temperatures. Under these reaction temperatures, twocompeting cracking reactions, thermal cracking and catalytic cracking,occur. Thermal cracking contributes to the formation of lighterproducts, mainly dry gas and coke, while catalytic cracking increasespropylene yield. Therefore, the residence time in the downflow reactoris relatively short, e.g., less than about 1 second, and in certainembodiments about 0.2-0.7 seconds, to minimize thermal cracking.Undesirable secondary reactions such as hydrogen-transfer reactions,which consume olefins, are suppressed due to the very short residencetimes. To maximize conversion during the short residence time, a highcatalyst to oil ratio is used, e.g., greater than 20:1, and catalystsand the feedstock are admixed and dispersed at the reactor inlet andseparated immediately at the reactor outlet.

In certain embodiments, an FCC unit configured with a downflow reactoris provided that operates under conditions that promote formation ofolefins and that minimize olefin-consuming reactions, such ashydrogen-transfer reactions. FIG. 2 is a generalized process flowdiagram of an FCC unit 100 which includes a downflow reactor and can beused in the hybrid system and process according to the presentinvention. FCC unit 100 includes a reactor/separator 110 having areaction zone 114 and a separation zone 116. FCC unit 100 also includesa regeneration zone 118 for regenerating spent catalyst.

In particular, a charge 120 is introduced to the reaction zone, incertain embodiments also accompanied by steam or other suitable gas foratomization of the feed, and with an effective quantity of heated freshor hot regenerated solid cracking catalyst particles from regenerationzone 118 is also transferred, e.g., through a downwardly directedconduit or pipe 122, commonly referred to as a transfer line orstandpipe, to a withdrawal well or hopper (not shown) at the top ofreaction zone 114. Hot catalyst flow is typically allowed to stabilizein order to be uniformly directed into the mix zone or feed injectionportion of reaction zone 114.

The bottoms fraction from the fractionating zone serves as the charge tothe FCC unit 100, alone or in combination with an additional feed asdiscussed above. The charge is injected into a mixing zone through feedinjection nozzles typically situated proximate to the point ofintroduction of the regenerated catalyst into reaction zone 114. Thesemultiple injection nozzles result in the catalyst and oil mixingthoroughly and uniformly. Once the charge contacts the hot catalyst,cracking reactions occur. The reaction vapor of hydrocarbon crackedproducts, unreacted feed and catalyst mixture quickly flows through theremainder of reaction zone 114 and into a rapid separation zone 116 atthe bottom portion of reactor/separator 110. Cracked and uncrackedhydrocarbons are directed through a conduit or pipe 124 to aconventional product recovery section known in the art.

If necessary for temperature control, a quench injection can be providednear the bottom of reaction zone 114 immediately before the separationzone 116. This quench injection quickly reduces or stops the crackingreactions and can be utilized for controlling cracking severity andallows for added process flexibility.

The reaction temperature, i.e., the outlet temperature of the downflowreactor, can be controlled by opening and closing a catalyst slide valve(not shown) that controls the flow of regenerated catalyst fromregeneration zone 118 into the top of reaction zone 114. The heatrequired for the endothermic cracking reaction is supplied by theregenerated catalyst. By changing the flow rate of the hot regeneratedcatalyst, the operating severity or cracking conditions can becontrolled to produce the desired yields of light olefinic hydrocarbonsand gasoline.

A stripper 132 is also provided for separating oil from the catalyst,which is transferred to regeneration zone 118. The catalyst fromseparation zone 116 flows to the lower section of the stripper 132 thatincludes a catalyst stripping section into which a suitable strippinggas, such as steam, is introduced through streamline 134. The strippingsection is typically provided with several baffles or structured packing(not shown) over which the downwardly flowing catalyst passescounter-currently to the flowing stripping gas. The upwardly flowingstripping gas, which is typically steam, is used to “strip” or removeany additional hydrocarbons that remain in the catalyst pores or betweencatalyst particles.

The stripped or spent catalyst is transported by lift forces from thecombustion air stream 128 through a lift riser of the regeneration zone118. This spent catalyst, which can also be contacted with additionalcombustion air, undergoes controlled combustion of any accumulated coke.Flue gases are removed from the regenerator via conduit 130. In theregenerator, the heat produced from the combustion of the by-productcoke is transferred to the catalyst raising the temperature required toprovide heat for the endothermic cracking reaction in the reaction zone114.

In one embodiment, a suitable FCC unit 100 that can be integrated intothe system of FIG. 1 that promotes formation of olefins and thatminimizes olefin-consuming reactions includes a high severity fluidizedcatalytic cracking reactor, can be similar to those described in U.S.Pat. No. 6,656,346, and US Patent Publication Number 2002/0195373, bothof which are incorporated herein by reference. Important properties ofdownflow reactors include introduction of feed at the top of the reactorwith downward flow, shorter residence time as compared to riserreactors, and high catalyst to oil ratio, e.g., in the range of about20:1 to about 30:1.

In general, the operating conditions for the reactor of a suitabledownflow FCC unit include:

reaction temperature of about 550° C. to about 650° C., in certainembodiments about 580° C. to about 630° C., and in further embodimentsabout 590° C. to about 620° C.;

reaction pressure of about 1 Kg/cm² to about 20 Kg/cm², in certainembodiments of about 1 Kg/cm² to about 10 Kg/cm², in further embodimentsof about 1 Kg/cm² to about 3 Kg/cm²;

contact time (in the reactor) of about 0.1 seconds to about 30 seconds,in certain embodiments about 0.1 seconds to about 10 seconds, and infurther embodiments about 0.2 seconds to about 0.7 seconds; and

a catalyst to feed ratio of about 1:1 to about 40:1, in certainembodiments about 1:1 to about 30:1, and in further embodiments about10:1 to about 30:1.

In certain embodiments, an FCC unit configured with a riser reactor isprovided that operates under conditions that promote formation ofolefins and that minimizes olefin-consuming reactions, such ashydrogen-transfer reactions. FIG. 3 is a generalized process flowdiagram of an FCC unit 200 which includes a riser reactor and can beused in the hybrid system and process according to the presentinvention. FCC unit 200 includes a reactor/separator 210 having a riserportion 212, a reaction zone 214 and a separation zone 216. FCC unit 200also includes a regeneration vessel 218 for regenerating spent catalyst.

Hydrocarbon feedstock is conveyed via a conduit 220, and in certainembodiments also accompanied by steam or other suitable gas foratomization of the feed, for admixture and intimate contact with aneffective quantity of heated fresh or regenerated solid crackingcatalyst particles which are conveyed via a conduit 222 fromregeneration vessel 218. The feed mixture and the cracking catalyst arecontacted under conditions to form a suspension that is introduced intothe riser 212.

In a continuous process, the mixture of cracking catalyst andhydrocarbon feedstock proceed upward through the riser 212 into reactionzone 214. In riser 212 and reaction zone 214, the hot cracking catalystparticles catalytically crack relatively large hydrocarbon molecules bycarbon-carbon bond cleavage.

During the reaction, as is conventional in FCC operations, the crackingcatalysts become coked and hence access to the active catalytic sites islimited or nonexistent. Reaction products are separated from the cokedcatalyst using any suitable configuration known in FCC units, generallyreferred to as the separation zone 216 in FCC unit 200, for instance,located at the top of the reactor 210 above the reaction zone 214. Theseparation zone can include any suitable apparatus known to those ofordinary skill in the art such as, for example, cyclones. The reactionproduct is withdrawn through conduit 224.

Catalyst particles containing coke deposits from fluid cracking of thehydrocarbon feedstock pass from the separation zone 214 through aconduit 226 to regeneration zone 218. In regeneration zone 218, thecoked catalyst comes into contact with a stream of oxygen-containinggas, e.g., pure oxygen or air, which enters regeneration zone 218 via aconduit 228. The regeneration zone 218 is operated in a configurationand under conditions that are known in typical FCC operations. Forinstance, regeneration zone 218 can operate as a fluidized bed toproduce regeneration off-gas comprising combustion products which isdischarged through a conduit 230. The hot regenerated catalyst istransferred from regeneration zone 218 through conduit 222 to the bottomportion of the riser 212 for admixture with the hydrocarbon feedstockand noted above.

In one embodiment, a suitable FCC unit 200 that can be integrated intothe system of FIG. 1 that promotes formation of olefins and thatminimizes olefin-consuming reactions includes a high severity fluidizedcatalytic cracking reactor, can be similar to that described in U.S.Pat. Nos. 7,312,370, 6,538,169, and 5,326,465.

In an alternative embodiment, liquid products from fractionating zone16, including the bottoms fraction, the middle distillate fraction andthe naphtha fraction, can be separately introduced into one or moreseparate riser reactors of a FCC unit having multiple risers. Forinstance, the bottoms fraction can be introduced via a main riser, and astream of naphtha and/or middle distillates can be introduced via asecondary riser. In this manner, olefin production can be maximizedwhile minimizing the formation methane and ethane, since differentoperating conditions can be employed in each riser.

In general, the operating conditions for the reactor of a suitable riserFCC unit include:

reaction temperature of about 480° C. to about 650° C., in certainembodiments about 500° C. to about 620° C., and in further embodimentsabout 500° C. to about 600° C.;

reaction pressure of about 1 Kg/cm² to about 20 Kg/cm², in certainembodiments of about 1 Kg/cm² to about 10 Kg/cm², in further embodimentsof about 1 Kg/cm² to about 3 Kg/cm²;

contact time (in the reactor) of about 0.7 seconds to about 10 seconds,in certain embodiments of about 1 seconds to about 5 seconds, in furtherembodiments of about 1 seconds to about 2 seconds; and

a catalyst to feed ratio of about 1:1 to about 15:1, in certainembodiments of about 1:1 to about 10:1, in further embodiments of about8:1 to about 20:1.

A catalyst that is suitable for the particular charge and the desiredproduct is conveyed to the fluidized catalytic cracking reactor withinthe FCC reaction and separation zone. In certain embodiments, to promoteformation of olefins and minimize olefin-consuming reactions, such ashydrogen-transfer reactions, an FCC catalyst mixture is used in the FCCreaction and separation zone, including an FCC base catalyst and an FCCcatalyst additive.

In particular, a matrix of a base cracking catalyst can include one ormore clays such as kaolin, montmorilonite, halloysite and bentonite,and/or one or more inorganic porous oxides such as alumina, silica,boria, chromia, magnesia, zirconia, titania and silica-alumina. The basecracking catalyst preferably has a bulk density of 0.5 g/ml to 1.0 g/ml,an average particle diameter of 50 microns to 90 microns, a surface areaof 50 m²/g to 350 m²/g and a pore volume of 0.05 ml/g to 0.5 ml/g.

A suitable catalyst mixture contains, in addition to a base crackingcatalyst, an additive containing a shape-selective zeolite. The shapeselective zeolite referred to herein means a zeolite whose pore diameteris smaller than that of Y-type zeolite, so that hydrocarbons with onlylimited shape can enter the zeolite through its pores. Suitableshape-selective zeolite components include ZSM-5 zeolite, zeolite omega,SAPO-5 zeolite, SAPO-11 zeolite, SAPO34 zeolite, and pentasil-typealuminosilicates. The content of the shape-selective zeolite in theadditive is generally in the range of 20 to 70 wt %, and preferably inthe range of 30 to 60 wt %.

The additive preferably has a bulk density of 0.5 g/ml to 1.0 g/ml, anaverage particle diameter of 50 microns to 90 microns, a surface area of10 m²/g to 200 m²/g and a pore volume of 0.01 ml/g to 0.3 ml/g.

A percentage of the base cracking catalyst in the catalyst mixture canbe in the range of 60 to 95 wt % and a percentage of the additive in thecatalyst mixture is in a range of 5 to 40 wt %. If the percentage of thebase cracking catalyst is lower than 60 wt % or the percentage ofadditive is higher than 40 wt %, high light-fraction olefin yield cannotbe obtained, because of low conversions of the feed oil. If thepercentage of the base cracking catalyst is higher than 95 wt %, or thepercentage of the additive is lower than 5 wt %, high light-fractionolefin yield cannot be obtained, while high conversion of the feed oilcan be achieved. For the purpose of this simplified schematicillustration and description, the numerous valves, temperature sensors,electronic controllers and the like that are customarily employed andwell known to those of ordinary skill in the art of fluid catalystcracking are not included. Accompanying components that are inconventional hydrocracking units such as, for example, bleed streams,spent catalyst discharge sub-systems, and catalyst replacementsub-systems are also not shown. Further, accompanying components thatare in conventional FCC systems such as, for example, air supplies,catalyst hoppers and flue gas handling are not shown.

In some embodiments, the apparatus and/or individual unit operations ofthe apparatus can include a controller to monitor and adjust the productslate as desired. A controller can direct any of the parameters withinthe apparatus depending upon the desired operating conditions, whichmay, for example, be based on customer demand and/or market value. Acontroller can adjust or regulate valves, feeders or pumps associatedwith one or more unit operations based upon one or more signalsgenerated by operator data input and/or automatically retrieved data.

In one embodiment, a controller can be in electronic communication with,and adjust, valves, feeders and/or pumps associated with the effluentfrom fractionator 16 to direct a quantity of one or more intermediatefractions (e.g., middle distillate via outlet 22 and/or naphtha viaoutlet 20) to the FCC reaction and separation unit, rather than passingthem on to respective product pools, if the desired product slateincludes an increase in olefin production at the sacrifice of these oneor more intermediate fractions.

In another embodiment, a controller can be in electronic communicationwith, and adjust, adjust thermostats, pressure regulators, valves,feeders and/or pumps associated with the first hydrocracking reactionzone 12 and/or the second hydrocracking reaction zone 46 to adjust theresidence time, hydrogen feed rate, operating temperature, operatingpressure, or other variables to modify the hydrocracker conversionefficiency.

The system and controller of one or more embodiments of the integratedhydrocracking and FCC apparatus provide a versatile unit having multiplemodes of operation, which can respond to multiple inputs to increase theflexibility of the recovered product. The controller can be implementedusing one or more computer systems which can be, for example, ageneral-purpose computer. Alternatively, the computer system can includespecially-programmed, special-purpose hardware, for example, anapplication-specific integrated circuit (ASIC) or controllers intendedfor a particular unit operation within a refinery.

The computer system can include one or more processors typicallyconnected to one or more memory devices, which can comprise, forexample, any one or more of a disk drive memory, a flash memory device,a RAM memory device, or other device for storing data. The memory istypically used for storing programs and data during operation of thesystem. For example, the memory can be used for storing historical datarelating to the parameters over a period of time, as well as operatingdata. Software, including programming code that implements embodimentsof the invention, can be stored on a computer readable and/or writeablenonvolatile recording medium, and then typically copied into memorywherein it can then be executed by one or more processors. Suchprogramming code can be written in any of a plurality of programminglanguages or combinations thereof

Components of the computer system can be coupled by one or moreinterconnection mechanisms, which can include one or more busses, e.g.,between components that are integrated within a same device, and/or anetwork, e.g., between components that reside on separate discretedevices. The interconnection mechanism typically enables communications,e.g., data, instructions, to be exchanged between components of thesystem.

The computer system can also include one or more input devices, forexample, a keyboard, mouse, trackball, microphone, touch screen, andother man-machine interface devices as well as one or more outputdevices, for example, a printing device, display screen, or speaker. Inaddition, the computer system can contain one or more interfaces thatcan connect the computer system to a communication network, in additionor as an alternative to the network that can be formed by one or more ofthe components of the system.

According to one or more embodiments of the integrated crackingapparatus, the one or more input devices can include sensors and/or flowmeters for measuring any one or more parameters of the apparatus and/orunit operations thereof. Alternatively, one or more of the sensors, flowmeters, pumps, or other components of the apparatus can be connected toa communication network that is operatively coupled to the computersystem. Any one or more of the above can be coupled to another computersystem or component to communicate with the computer system over one ormore communication networks. Such a configuration permits any sensor orsignal-generating device to be located at a significant distance fromthe computer system and/or allow any sensor to be located at asignificant distance from any subsystem and/or the controller, whilestill providing data therebetween. Such communication mechanisms can beaffected by utilizing any suitable technique including but not limitedto those utilizing wireless protocols.

Although the computer system is described by way of example as one typeof computer system upon which various aspects of the integrated crackingapparatus can be practiced, it should be appreciated that the inventionis not limited to being implemented in software, or on the computersystem as exemplarily shown. Indeed, rather than implemented on, forexample, a general purpose computer system, the controller, orcomponents or subsections thereof, can alternatively be implemented as adedicated system or as a dedicated programmable logic controller (PLC)or in a distributed control system. Further, it should be appreciatedthat one or more features or aspects of the integrated crackingapparatus can be implemented in software, hardware or firmware, or anycombination thereof. For example, one or more segments of an algorithmexecutable by a controller can be performed in separate computers, whichin turn, can be in communication through one or more networks.

In some embodiments, one or more sensors and/or flow meters can beincluded at locations throughout the integrated cracking apparatus,which are in communication with a manual operator or an automatedcontrol system to implement a suitable process modification in aprogrammable logic controlled integrated cracking apparatus. In oneembodiment, an integrated cracking apparatus described herein includes acontroller which can be any suitable programmed or dedicated computersystem, PLC, or distributed control system. The flow rates of certainproduct streams from the fractionator 16 and the FCC reaction andseparation zone 32 can be measured, and flow can be redirected asnecessary to meet the requisite product slate.

In certain embodiments, under control of an operator or a controller asdescribed herein, the integrated cracking apparatus can operate withreduced efficiency catalyst in the first or second hydrocrackingreaction zones 12, 46 to favor bottoms production. i.e., having a levelof activity that is conventionally considered unsuitable for use intheir respective operations. In this manner, the quantity of feed to theFCC reaction and separation zone 32 is increased, thereby resulting inan increase in its products olefins and/or gasoline via outlets 36and/or 38.

In further embodiments, under control of an operator or a controller asdescribed herein, either or both of the first and second hydrocrackingzones 12, 46 can operate with a level of hydrogen feed that isrelatively low, i.e., at a level that is conventionally consideredunsuitable for use in their respective operations. In this manner, theexpense of hydrogen is reduced, while the quantity of feed to the FCCreaction and separation zone 32 is increased, thereby resulting in anincrease in its products olefins and/or gasoline via outlets 36 and/or38.

Factors that can result in various adjustments or controls includecustomer demand of the various hydrocarbon products, market value of thevarious hydrocarbon products, feedstock properties such as API gravityor heteroatom content, and product quality (e.g., gasoline and middistillate indicative properties such as octane number for gasoline andcetane number for mid distillates).

Example

A feedstock containing demetallized oil and light and heavy vacuum gasoil fractions was hydrocracked in a first stage of hydrocracking unit.The feedstock blend was characterized by a density of 889.5 Kg/L, 2.32 W% of sulfur, 886 ppmw of nitrogen, 12.1 W % of hydrogen and 1.2 W % ofMicro carbon residue. The initial boiling point was 216° C.; 5 W %, 337°C.; 10 W %, 371° C.; 30 W %, 432° C.; 50 W %, 469° C.; 70 W %, 510° C.,90 W %, 585° C.; 95 W %, 632; and the final boiling point was 721° C. Asilica-alumina based catalyst was used in the first hydrocrackingreaction zone. The operating conditions for the first stage were: 115bars of hydrogen partial pressure, a temperature of 385° C., a liquidhourly space velocity of 0.27 h⁻¹, and a hydrogen to oil ratio of1263:1.

The first stage hydrocracking reaction zone effluent stream wasseparated and the unconverted hydrocracker bottoms stream (44 W %)having an initial boiling point of 370° C. was then sent to a highseverity FCC unit with a downer reactor. A base catalyst of H-USY typezeolite with low acid site density (75 V %) and an additive, 10 W %commercial ZSM-5 (25 V %) was used in the high severity FCC unit. Thecatalyst to oil ratio (mass:mass) was 30:1. The downer temperature was630° C. 93 W % of the hydrocracker bottoms were converted in the highseverity FCC unit.

The cycle oil stream (6 W %) having an initial boiling point of 235° C.was passed to the second stage hydrocracking reaction zone. Theoperating conditions for the second stage were: 115 bars of hydrogenpartial pressure, a temperature of 370° C., a liquid hourly spacevelocity of 0.80 h⁻¹, and a hydrogen to oil ratio of 1263:1.

The overall conversion was 100 V % and the yields are summarized inTable 2 below.

TABLE 2 Yield W % V % H₂S 2.6 NH₃ 0.1 CO + CO₂ 0.0 H₂, C₁, C₂ 2.8 C₂ 0.3C₂= 1.8 C₃-C₄ 2.6 C₃= 11.1 C₄ 1.6 C₄= 10.5 Naphtha 12.8 15.9 MiddleDistillate 41.7 42.9 Gasoline 14.1 18.5 Coke 0.2 Total Yield* 102.2Total Liquid Yield 68.6 77.3 *Note that the yield in excess of 100% isdue to the addition of hydrogen in the hydrocracking unit.

The process yielded 41.7 W % of middle distillate product and 11.1 W %of propylene product (based on the initial feed), with no residue. Thetotal gasoline production is estimated to be 24.0 W %, which includesthe high severity FCC unit gasoline and hydrocracker naphtha afterdownstream reformer processing to increase the research octane numberfrom a value of about 80 to about 95 for use as gasoline (which slightlydecreases the overall yield as is conventionally known).

The method and system of the present invention have been described aboveand in the attached drawings; however, modifications will be apparent tothose of ordinary skill in the art and the scope of protection for theinvention is to be defined by the claims that follow.

1. An integrated process for conversion of a feedstock containinghydrocarbons having a boiling point greater than 300° C. that includeshydrocracking and fluidized catalytic cracking, the process comprising:a. introducing the feedstock and hydrogen into a first hydrocrackingreaction zone containing a first hydrocracking catalyst to produce afirst zone effluent; b. passing the first zone effluent to afractionating zone to produce at least a low boiling fraction and a highboiling fraction, and optionally one or more intermediate fractions; c.passing the bottoms fraction to a fluidized catalytic cracking reactionand separation zone operating under conditions that promote formation ofolefins and gasoline and that minimize olefin-consuming reactions; d.recovering olefins from the fluidized catalytic cracking reaction andseparation zone; e. recovering gasoline from the fluidized catalyticcracking reaction and separation zone; f. conveying at least a portionof remaining cycle oil from the fluidized catalytic cracking reactionand separation zone, and hydrogen, to a second hydrocracking reactionzone containing a second hydrocracking catalyst to produce a secondstage effluent; and g. recycling at least a portion of the second stageeffluent to the fractionating zone and/or the first hydrocrackingreaction zone.
 2. The process of claim 1, wherein step (g) comprisesconveying a portion of the second stage effluent to the fractionatingzone.
 3. The process of claim 1, wherein step (g) comprises conveying aportion of the second stage effluent to the first hydrocracking reactionzone.
 4. The process of claim 1, further comprising discharging gasesfrom the fluidized catalytic cracking reaction and separation zone; 5.The process of claim 1, further comprising recovering naphtha from thefractionating zone.
 6. The process of claim 1, further comprisingrecovering middle distillates from the fractionating zone.
 7. Theprocess of claim 1, wherein a portion of the bottoms fraction from thefractionating zone is bled.
 8. The process of claim 7, wherein theportion that is bled is about 1 V % to about 10 V % of the bottomsfraction.
 9. The process of claim 1, wherein step (c) further includesintroducing an additional feedstock to the fluidized catalytic crackingreaction and separation zone.
 10. The process of claim 1, wherein thefluidized catalytic cracking reaction and separation zone includes adownflow reactor.
 11. The process of claim 1, wherein the fluidizedcatalytic cracking reaction and separation zone includes a riserreactor.
 12. The process of claim 1, wherein step (c) comprisesconveying a fluidized cracking catalyst mixture including the fluidizedcracking catalyst as a fluidized cracking base catalyst, and a catalystadditive.
 13. The process of claim 12, wherein the fluidized crackingbase catalyst comprises about 60 wt % to about 95 wt % of the totalfluidized cracking catalyst mixture.
 14. The process of claim 12,wherein the fluid cracking base catalyst is selected from the groupconsisting of clays and inorganic porous oxides.
 15. The process ofclaim 13, wherein the fluid cracking base catalyst has a bulk density of0.5 g/ml to 1.0 g/ml, an average particle diameter of 50 microns to 90microns, a surface area of 50 m²/g to 350 and a pore volume of 0.05 ml/gto 0.5 ml/g.
 16. The process of claim 12, wherein the catalyst additiveincludes a shape-selective zeolite.
 17. The process of claim 16, whereinthe shape selective zeolite is characterized by an average pore diameterthat is less then the average pore diameter of Y-type zeolite.
 18. Theprocess of claim 16, wherein the shape selective zeolite is selectedfrom the group consisting of ZSM-5 zeolite, zeolite omega, SAPO-5zeolite, SAPO-11 zeolite, SAPO-34 zeolite, pentasil-typealuminosilicate, and combinations comprising at least one of theforegoing shape selective zeolite.
 19. The process of claim 16, whereinthe shape selective zeolite having a bulk density of 0.5 g/ml to 1.0g/ml, an average particle diameter of 50 microns to 90 microns, asurface area of 10 m²/g to 200 m²/g and a pore volume of 0.01 ml/g to0.3 ml/g.
 20. The process of claim 16, wherein the fluid crackingcatalyst mixture includes about 5 wt % to about 40 wt % of the catalystadditive.
 21. The process of claim 16, wherein the catalyst additivecomprises about 20 wt % to about 70 wt % shape-selective zeolite. 22.The process of claim 16, wherein the catalyst additive comprises about30 wt % to about 60 wt % shape-selective zeolite.
 23. An integratedcracking apparatus comprising: a first hydrocracking reaction zonecontaining a first hydrocracking catalyst, and including a feed inlet influid communication with a source of feedstock and a source of hydrogenand a first zone outlet; a fractionating zone including an inlet influid communication with the first zone outlet, an overhead gas outlet,a bottoms outlet, and optionally one or more intermediate fractionoutlets; a fluidized catalytic cracking reaction and separation zoneoperating under conditions that promote formation of olefins andgasoline and that minimize olefin-consuming reactions, the fluidizedcatalytic cracking reaction and separation zone including at least oneinlet in fluid communication with the bottoms outlet of thefractionating zone, an olefin outlet, a gasoline outlet, and at leastone cycle oil outlet, a second hydrocracking reaction zone containing asecond hydrocracking catalyst, and including at least one inlet in fluidcommunication with cycle oil outlet of the fluidized catalytic crackingreaction and separation zone and a source of hydrogen gas, and a secondzone outlet in fluid communication with the inlet of the fractionatingzone.
 24. This apparatus of claim 22, wherein the second stage effluentoutlet is also in fluid communication with the feed inlet of the firsthydrocracking reaction zone.
 25. The apparatus of claim 22, furthercomprising a bleed outlet in fluid communication with the bottoms outletof the fractionating zone.
 26. The apparatus of claim 22, wherein theinlet of the fluidized catalytic cracking reaction and separation zoneis in fluid communication with a source of feedstock that is separatefrom the bottoms outlet of the fractionating zone.
 27. The apparatus ofclaim 22, wherein the fluidized catalytic cracking reaction andseparation zone includes a downflow reactor.
 28. The apparatus of claim22, wherein the fluidized catalytic cracking reaction and separationzone includes a riser reactor.
 29. The apparatus of claim 22, furthercomprising at least one flow meter constructed and arranged to measureproduction at one of the outlets; and a controller in electroniccommunication with the flow meter programmed to instruct performance ofan adjustment based on the measured production.
 30. The apparatus ofclaim 29, wherein the measure production is the flow rate at the olefinoutlet.
 31. The apparatus of claim 29, wherein the adjustment modifiesconversion efficiency in the first hydrocracking reaction zone or thesecond hydrocracking reaction zone.